High-speed tool-steel.



HIGH-SPEED TOOL-STEEL.

No Drawing.

Specification of Letters Patent.

Patented May 5 1914.

Application filed January 30, 1914. Seria1 No. 815,402.

To all whom it may concern Be it known that I, Rnoonrrrn FURNESS, a citizen of the United States, residing at Jenkintcwn, county of Montgomery and State of Pennsylvania, have invented a new and useful Improvement. in High-Speed Tool-Steel, of which the following'is a full, clear, and exact description.

The object of'my invention is to produce a new and improved high speed tool steel which will endure for a greater length of time at the same cut feed and speed, or which can operate at a higher cut feed and speed andtherefore remove more metal in a given length of time, than any high speed tool steel heretofore known.

The invention consists of steel containing vanadium, chromium, tungsten and cobalt in certain definite proportions. The following is a typical composition and one which careful experiment has shown to produce the best results: iron, 74 per cent; vanadium, 1.5 per cent., chromium, 3 per cent; tungsten, 17.5 per cent; cobalt, 4 per cent.. The iron should contain about .65 per cent. of carbon, the proportion of which must not exceed one per cent., and may contain the usual small percentages of natural alloys or impurities, such as manganese, silicon, titanium, phosphorus and sulfur, present in comparatively low carbon steel, the percentage of vanadium should not exceed two per cent. nor be less than one per cent. The cobalt may vary within a range of from three to seven per cent., the chromium within a range of from two and one half to four per cent., and the tungsten within a range of from sixteen and one half to twenty per cent. If the steel contains a'proportion of any of the enumer ated alloying metals less than the minimum specified, the durability of the steel'becomes so pronouncedly affected as to render the same measurably inferior to high speed tool steels of other known combinations of elements. If, on the other hand, the maximum proportions specified are exceeded in anygiven instance, the same result, together with brittleness, develops. It should also be mentioned that if the proportions of any one of the alloying ingredients specified are increased or diminished beyond or belowthose of the typical composition above defined, the proportions of the other alloying ingredients should be increased or diminished accordingly, so as to maintain approxi- I am aware that various patents for high speed and other steels have issued, and some literature has been published, in which the use of one or more of all the above ingredients, and even the precise combination of ingredients hereinbefore specified, have been suggested; but such patents disclose no really useful information to those skilled in the art, as the possible relative and absolute percentages of the ingredients are almost infinite, whereas unless the relative and absolute percentages are fixed and determined within narrow limits, no efficient cutting steel would be produced and many steels containing the precise ingredients hereinbefore mentioned as essential to a composition embodying my invention would be worsethan worthless for tool steel or for any other purpose. In myv invention, on the contrary, any one skilled in the art can produce an effective and superior high speed tool steel without the necessity of any experimentation whatever, the ingredients beingmixed and the steel manufactured in no way different from that characterizing other known compositions of high speed tool steel and well known to those skilled in the art.

While I have mentioned that the steel above described is adapted especially for high speed tool steel, it is also capable of other uses, as for example" any device for v 1 working hot metal, such as gripper dies, nut piercers and header dies. For-such purposes the steel should contain from .20 to .60 per cent. of carbon.

Having now full described my invention,

what-"I claim and desire to protect by Letters Patent is:

1. A high speed tool steel containing vanadium, from one to two per cent; cobalt, from 8 to 7 per cent.; chromium, from 2.5 to 4- per cent., and tungsten, from 16.5 to 20 per cent.

2. A h-'gh speed tool steel containing. vanadium, about 1.5 per cent; cobalt about 4 per cent; chromium, about .3 per cent;

and tungsten, about 17.5 per cent.

3. A high speed toolsteel containing vanadium, from one to two per cent., co-

balt, from 3 to 7 per cent.; chromium, from 2.5 to 4 per cent.; and tungsten from 16.5 to 20 per cent. 5 the relative percentages of the vanadium, cobalt, chromium and tungsten 5 being approximately in the ratio of 1.5, 4;, 3-

and 17.5.

In testimony of which invention have RADCLYFFE FURNESS. Witnesses:

M. M. HAMILTON, E. E. WALL. 

